198 Chapter 9 same MPLAB controls and facilities. However, if the schematic needs modifying, it must be re-edited in ISIS itself. 9.5. Hardware Testing Hardware construction will be covered in more detail in Chapter 10. For the moment, we will assume that suitable hardware has been constructed for MOT1 and we are ready to test it. When the program has been fully debugged in a simulator, it can be downloaded to the chip. In some cases, the chip must be programmed before fitting, specifically 16F84A-based circuits. For most current PIC chips, however, it is preferable to program it in-circuit via the six-pin in-circuit serial programming (ICSP) connection (see Chapter 7). In-circuit debugging, as described in Chapter 7, can also be used in the final stages of testing. This allows the program to be exercised in conjunction with the final hardware, using the debugging tools in MPLAB. The state of the registers in response to real inputs can then be monitored for fault- finding purposes. The target hardware layout and connections should be carefully checked and tested before inserting the chip. The populated circuit board should be inspected for correct assembly; wrong component orientation, solder bridges between tracks and dry joints are common